Photographic process

ABSTRACT

A photographic element having improved matting properties is prepared by deionizing or deashing an aqueous gelatin solution containing at least about 5 percent by weight gelatin and then adding a matting agent which comprises discrete particles of a polymer containing free carboxyl groups to the resulting aqueous gelatin solution. The resulting gelatin solution containing the matting agent can be employed with other addenda employed in photographic materials. Deionizing can be carried out by passing the aqueous gelatin solution through an ion-exchange resin or deashing can be effected by washing the gelatin solution with an aqueous acid solution.

[111 3,767,448 Oct. 23, 1973 1' PHOTOGRAPHICVYPROCESS 75 lnventor:Philip F. Hutton, l-lilton, N'.Y.'

[73] Assignee: Eastman Kodak Company,

Rochester, NY.

[22] Filed: 7 Nov. 29, 1971 [21] Appl. No.: 203,014

[52] U.S. Cl. 117/34, 96/87 R, 106/135,

117/16,117/29, 117/164, 260/117, 260/118 [51] int. Cl. B4411 l/094, G03cH32 [58] Field of Search 117/34, 164; 976/87 R, 114.7; 106/135; 260/117,118

[56] References Cited UNITED STATES PATENTS 3,687,703 8/1972 Ohashi etal 117/34 3,370,951 2/1968 Hasenauch et a1 96/87 R 2,322,037 6/1943Linquist 96/114.7 2,992,213 7/1961 Gates et a1 96/87 R 2,391,181 12/1945Minsk et al. 96/87 R 3,411,907 11/1968 Whitmore 913/87 R FOREIGN PATENTSOR APPLICATIONS 528,850 ll/l940 Great Britain 96187 R 837,529 6/1960Great Britain 96/87 R I Primary Examiner-William D. Martin AssistantExaminerwilliam' R. Trenor AttorneyRobert W. Hampton et al.

[57] ABSTRACT A photographic element having improved matting propertiesis prepared by deionizing or deashing an aqueous gelatin solutioncontaining at least about 5 deashing can be effected by washing thegelatin solution with an aqueous acid solution.

7 Claims, No Drawings I 1 I PI-IOTOGRAPHIC PROCESS BACKGROUNDO FT HEINVENTION This invention relates to preparation of photographicmaterials containingmatting agents. It also relates to photographicmaterials containing the .described'matting agents in gelatincompositions.

DESCRIPTION OF THE STATE OF THE ART It is known to employ matting agentssuch as copoly-methylmethacrylate methacrylic acid beads in photographicmaterials. Photographic materials containing such matting "agentsaredescribed, for example, in U.S. Pat. No. 2,322,037 of Lindquist issuedJun. 15, 1943; Such polymers have also been employed for other purposesin photographic materials such' as described in U.S. Pat. No. 2,992,101of .lelley et a1, issued Jul. 11,1961. I

Various matting agents are also known in photographic materials which'donot contain free carboxyl groups. Such matting agents include, forexample, polyme thylmethacrylate particles as describedin U.S. Pat. No.3,411,907 of Whitrnore and Coryell issued-Nov. 19, 1968. Various othermatting agents are described in British Pat. No. 837,529 published-Jun.15, 1960.

. In the preparation of photographic materials contain-v containing atleast about 5 percent by weight gelatin, preferably at least about 8percent to about percent by weight gelatin, and coating the resultingcomposition on the support, the improvement comprising deing mattingagents in gelatin wherein the matting agents I are polymers containingfree carboxyl groups, a problem has been encountered which involves thetendency of the matting agent to dissolve during preparation of thematerials for coating on a suitable support. This problem is especiallytroublesome when matting agent particles comprisingcopolymethylmethacrylate methacrylic acid are added to an aqueoussolution containing more than about 4 percent gelatin and, inparticular, a solution containing more than about 8 percent by'weightgelatin. Processes up to this point have resulted in less than thedesired matting properties in SUMMARY OF THE INVENTION It has been foundaccording to the invention that photographic materials having improvedmatting agent properties, containing a matting agent which comprises apolymer containing free carboxyl groups, can be provided by deionizingor deashing an aqueous gelatin solution, containing more than about 5percent gelatin, before adding the described matting agent to thegelatin solution. Deionizing can be carried out as described in BritishPat. No. 528,850 published Nov. 8, 1940. Deashing of the gelatinsolution can be carried out as described in Example '1 of U.S. Pat. No.2,992,213 of Gates et al issued Jul. 11, I961.

DETAILED DESCRIPTION OF THE INVENTION by adding the matting agent to anaqueous solution ionizing or deashing the aqueous gelatin solutionbefore adding the matting agent. While the mechanism by which improvedmatting properties is provided according to this process is notcompletely understood, it is believed that the dissolution of thepolymeric particles, also known as beads, is caused by the presence ofcalcium ions. It is believed that the deionizing or deashing procedureprovides removal of the calcium ions from the gelatin thereby helping toprevent dissolution of the polymeric particles.

While the process of the invention is applicable to a range of mattingagents, preferred matting agents are the alkali soluble polymeric estersof acrylic and methacrylic acid as exemplified bycopolymethylmethacrylate methacrylic acid (52 percent methacrylic acid).Such matting agents are described, for example, in U.S. Pat. No.2,391,181 and U.S. Pat. No. 2,992,101. Particularly suitable mattingagents are alkali soluble glkylacrylate-acrylic acid copolymers whereonthe acrylic acid monomer may be substituted by an alkyl group, e.g.methacrylic acid. I

The process of the invention is especially suitable when employinggelatin solutions containing a high concentration of gelatin such as, atleast about 5 percent by weight gelatin, typically at least about 8percent to about 20 percent by weight gelatin.

The described matting agent particles or beads are added to the aqueousgelatin solution in a range of concentration which is typically about0.5 percent to about 15 percent by weight of the described gelatinsolution.

The process, as described, is particularly advantageous when thedescribed polymeric particles or beads are added to the gelatin solutionin a concentration of at least 5 percent by weight of the gelatinsolution. The problem of this dissolution of the described polymericparticles or beads is especially noticeable above this concentration.

A range of deionizing procedures can be employed, however, the gelatinsolution is preferably treated with an ion-exchange resin such as ananionic resin available under the trade name AMBERLITE IRA-900 from theRohm and Haas Company of Philadelphia, Pennsylvania, U.S.A. A cationicresin sold under the trade name AMBERLITE 200 is also suitable. Thiscationic resin is available under this trade name from Rohm and HaasCompany of Philadelphia, Pa., U.S.A. These ionexchange resins are knownin the photographic art and available commercially.

The described deashing procedure can be carried out by treating thegelatin with an acid solution such as an aqueous acetic acid solution.Such acid treatments and deashing procedures have been employed forpreparing gelatin for photographic subbing as described in U.S. Pat. No.2,992,213 of Gates et al issued Jul. 11, 1961. For example, gelatin canbe treated by leaching in an aqueous alkaline solution such as anaqueous ammonia or alkali metal hydroxide or alkali metal carbonatesolution for a time such as l to 6 hours at a pH of 8 to 9.5 and at atemperature of about 15 to 20 C. After this alkaline treatment it can besubjected to washing with an aqueous acetic acid solution to removeundesired lOI'lS.

Various gelatins can be employed in the process of the invention.Gelatin for photographic purposes and the process of the invention isdescribed, for example, in the Theory of the Photographic Process editedby Mess and James, 3rd Edition, 1966, pages 45-54.

The particles of matting agent in the gelatin composition can beincorporated in l or more layers of the photographic element. Thegelatin composition containing the described matting agent can be in thephotosensitive silver halide emulsion layer and/or a layer contiguousthereto. Various methods can be employed for dispersing the particles inthe layer or layers. A gelatin layer or layer of other silver halidebinding agent containing the described particles of matting agents canbe coated as a protective layer over a silver halide emulsion layerand/or as a backing layer on a suitable support.

Photographic elements prepared according to the process of the inventioncontaining the described matting agents in a protective layer which isouter most from the support exhibit good resistance to abrasion.

The coverage of the described matting agents on a support for aphotographic element is subject to variation depending on the desireddegree of matting properties, processing conditions and the like.Typical coverage of the polymeric matting agents is about 0.75milligrams to about 5 milligrams of polymeric particles or beads persquare decimeter of support.

Various supports can be employed for compositions prepared according tothe invention. Typical supports are those employed in the photographicart. Typical supports are film, paper, glass or the like.

Various materials can be used in combination with the matting agents andgelatin in photographic materials as binding agents and for otherpurposes. Such binding agents include synthetic materials and naturalresins as described, for example, in U.S. Pat. No. 3,411,907 of Whitmoreand Coryell issued Nov. 19, 1968. This invention may be used withelements designed for color materials, for example, elements containingcolor-forming couples such as those described in Graham U.S. Pat.3,227,554; Vittum et al. U.S. Pat. 2,360,290 or elements to be developedin solutions containing color-forming couples such as described inMannes et al. U.S. Pat. No. 2,252,718.

Photographic materials prepared according to the process of theinvention can contain additional addenda which do not adversely affectthe matting properties of the described matting agents. These include,for example, various photosensitive silver halide emulsions, chemicalsensitizers for such emulsions, development modifiers, antifoggants,stabilizers, developing agents, hardeners, plasticizers, coating agents,brighteners, spectral sensitizing dyes, absorbing and filter dyes, andthe like as described, for example, in Dunn U.S. Pat. No. 3,297,446issued Jan. 10, 1967 and U.S. Pat. No. 3,411,907 of Whitmore and Coryellissued Nov. 19, 1968.

The following examples are included for a further understanding of theinvention.

Example 1 A. Into an aqueous 8 percent by weight bone gelatin solutionare dispersed copolymethylmethacrylatemethacrylic acid beads which havean average diameter of 3 microns. To the solution are added appropi'iatespreading and hardening agents. The solution is then coated on a filmsupport at the rate of 9.79 mg of gelatin/dm and 1.6 mg ofpolymethacrylate beads/dm'.

B. An element is prepared in a manner similar to (A) above except thebone gelatin solution is deionized using an ion-exchange resin asdescribed in British Pat. No. 528,850 in columns 1 and 2.

C. An element is prepared in a manner similar to (A) above except thebone gelatin solution is deashed by washing in an acid solution asdescribed in Example 1 in U.S. Pat. No. 2,992,213.

The results of Example 1 A, B and C indicate that the product of 1B and1C contains a significantly higher concentration of matting agentparticles or beads than the product produced by process 1A. On anarbitrary scale of 1 to 5 wherein 1 represents few matting agentparticles showing on the surface of the element and 5 represents a goodmatted surface of the element, the product of process A receives arating of l and the products of B and C receive a rating of 5.

Example 2 Three separate coatings are prepared as described in Example1A, B and C, except pig gelatin is employed in place of bone gelatin.

The results of Example 2A, B and C are similar to those of Example 1A, Band C. On the arbitrary scale described in Example 1, the product ofExample 2A receives a rating of 2 and the products of 2B and 2C receivea rating of 5.

Example 3 The procedure in Example 13 and 1C is repeated with theexception that the described gelatin solution containing the polymericparticles is coated on a photosensitive silver bromoiodide gelatinoemulsion layer on a film support. A photographic element having goodmatting properties is produced.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention.

I claim:

1. In a process for preparing a photographic element comprising asupport having thereon a gelatino composition comprising a matting agentwhich comprises discrete particles of a polymer containing enough freecarboxyl groups to cause said polymer to dissolve in an aqueous gelatinsolution containing at least 5% by weight gelatin when said particlesare blended with said aqueous gelatin solution;

which process comprises (1) adding said matting agent to said aqueousgelatin solution, (2) applying the resulting composition to said supportand (3) drying the resulting coated support;

the improvement which comprises deionizing or deashing said aqueousgelatin solution before adding said particles of said polymer.

2. The process of claim 1 wherein said matting agent is an alkylacrylate polymer containing free carboxyl groups.

3- The process of claim 1 wherein said matting agent is copoly (methylmethacrylate methacrylic acid).

4. The process of claim 1 wherein said matting agent is added to saidgelatin solution in a concentration of about 0.5 percent to about 15percent by weight of said gelatin solution.

5. The process of claim 1 wherein said gelatin soluthrough anion-exchange resin. tion contains about 5 percent to about 20 percent by7. The process of claim 1 wherein said deashing is weight gelatin.carried out by washing said gelatin solution with an 6. The process ofclaim 1 wherein said deionizing is aqueous acetic acid solution. carriedout by passing said aqueous gelatin solution 5

2. The process of claim 1 wherein said matting agent is an alkylacrylate polymer containing free carboxyl groups.
 3. The process ofclaim 1 wherein said matting agent is copoly (methyl methacrylate -methacrylic acid).
 4. The process of claim 1 wherein said matting agentis added to said gelatin solution in a concentration of about 0.5percent to about 15 percent by weight of said gelatin solution.
 5. Theprocess of claim 1 wherein said gelatin solution contains about 5percent to about 20 percent by weight gelatin.
 6. The process of claim 1wherein said deionizing is carried out by passing said aqueous gelatinsolution through an ion-exchange resin.
 7. The process of claim 1wherein said deashing is carried out by washing said gelatin solutionwith an aqueous acetic acid solution.